Electric communication system



Oct. 24, 1939. H. R. ALL ENSWORTH I 2,177,512

ELECTRIC COMMUNICATION SYSTEM Filed March 8, 1937 INVENTOR HARRY R ALLENSWORTH ATTORNEY Patented Oct. 24, 1939 UNlTED STATES QPYATENT OFFICE I 4 Claims.

My invention relates to electric communication systems and more particularly to that field or subject matter known to the art as emergency communication and has for its object new and improved means whereby the scope of usefulness of certain kinds of communication systems is enlarged, expanded and extended beyond otherwise inherent limitations and restrictions. According to my invention these objects are attained by new and novel means comprising electric circuits and networks whereby telephonic signaling and communication upon any suitable signal circuit is accomplished without in any way hindering the operation of, or impairing the normal functioning of, the signal circuit.

My invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawing forming a part of this application; with the understanding, however, that the invention is not confined to the one practical application herein selected for purposes of illustration nor is the invention confined to any strict conformity with the showing of the drawing which may be changed or modified so long as such changes and/or modifications mark no material departure from the salient features of the invention within the scope ofthe appendedclaims.

Illustrative of one, only, of'the important prac- '30 tical applications of my invention as shown in i 40 employing the circuit for telephonic communication. Where this is done, a telephone transmitter and receiver areusually connected in the circuit in series at one of the signal boxes. Similarly, at the central ofiice a'telephone transmitter and receiver are connected in the circuit and telephonic communication from the box to the central. ofiice' and vice versa, is made possible. In closed circuit systems the attention of the central office attendant is attracted to a telephone call from a signal box by openingand closing the circuit-by means provided atthe signal boxa prearranged number of times thus striking a signal in the central oflice.

Telephonic communication under such circumstances is not of the best. Furthermore, there is ever present the possibility of mutilating an alarm signal.

By the application of my invention to this circumstance telephonic communication of very high quality is made possible and the possibility .5 of, in any way, impairing the normal functioning of the signal circuit is eliminated.

Referring now to the accompanying drawing:

LI and L2 are the two sides of a fire alarm signal (box) circuit comprising battery I, recording de-="10 vice 2, sounding device 3 and signal boxes 4, 5, 6 and l, in series; any acceptable number of signal boxes may be comprised in the circuit, as indicated by dotted lines from boxes 4 and I, including boxes 5 and 6. The circuit is normally-"l5 closed. Each box, in addition to other functional devices, is equipped with a jack or other suitable means of connecting a telephone or other device in series with the circuit. Such a device (8) in the form of a conventional jack, 2o normally closed, is shown as part of signal box I. Operatively associated with the above well known emergency communication system, in the manner hereinafter disclosed, is an electric communication network comprising plug 9; the two con- 25 ductors connected to 9; Pl P2, P3, S and C; hand set HS comprising telephone transmitter T and telephone receiver R; break-make push button l0 and impulse emitter l I; together and collectively constituting a portable telephone. Also, Operatively associated with said emergency communication system is an electric communication system comprising line relays LR and LRZ, line signal LL, cut-off relay CO, answering jack l2 and multiple jack l3, with associated circuitsand appurtenances, together and collectively constituting a telephone switchboard line circuit Operatively associated with Li and L2 by means of condensers I4 and I5.

PI, P2 and P3 are three primary windings of a four winding transformer; S, the fourth winding, is secondary to Pl, P2 and P3. The three said primary windings together with telephone transmitter T are so connected as to form a divided circuit bridged by condenser C at points l5 and I6. I

The armature of impulse emitter II is a reed of magnetic material or an armature suitably poised on a leaf spring orother suitable means whereby the armature operates at the proper vibration frequency.

Assume now that plug 9 be inserted in jack 8; thereby the network comprising Pl, P2, P3, S, C, HS, Ill and II is connected in the signal circuit (Ll; L2) and becomes Operatively associated-'55 eat therewith. Break-make push button I0, upon being operated, disconnects telephone transmitter T from the network and substitutes therefore impulse emitter II which upon becoming energized attracts its armature which closes I! thus short circuiting I I which is thereby deenergized and its armature releases, opening I1; whereupon the same cycle of operation is repeated and continued so long as I8 is held closed. a

' The operation of I I thus sets up an undulatory impulse sequence or train in the transformer primary which undulatory impulse sequence is impressed and superinduced in the signal circuit by the operation of the telephone network. Impulse emitter Il may take the form of the well known electric buzzer, the operation of which will produce similar results in the transformer primary and network. h H 1 Furthermore, when break-make push button I0 is operated, I9 is closed shunting R and S. Shunting S reduces the impedance of the transformerprimaries to; impulse sequences emitted by the operation of II. Additionally, both booster and antisidetone characteristics are incorporated in said telephone network, as is shown. 1

The impedancesof-2 and 3 causes them to function as retardations orreactors to the undulatory current impulse sequences superinduced .in LI, L2 by the operation of I I; also, to current undulations superinduced in LI, L2 by the opering alternating current impulse sequences in LR "and 20 which causes LR to operate.

The operation of LR closest. I, which puts battery through the winding of slow to operate relay LE2, as is shown. LRZ being slow to operate will respond only to a prolonged, momentarily, closing j of ZI. Accordingly, slow to operate relay LE2 -will not respond to comparatively infrequent charging and dischargingof condensers I4 and I5 due to rise-and fall of E. M. F; in LI- and L2 caused by the operation of the signal circuit, or

other incidental charge and discharge of I4 and, I5. The operation of LRZeloses Hand 23.. The closing of 22 causes line signal'LL to operate.

The closing of .23 shunts the telephone switchboard line circuit at points 24 and 25 and holds LRcperated which holds LRZand LL operated until a switchboard plug is inserted in jack I2or I3,'which action puts battery on the sleeve of the jack thus'operating cut-oil relay CO which releases LR which in turn releases LE2. Thus the line signalis-restored bythe opening ofv 22; the holding shunt is opened by; the opening of 23 and the right back contact of CO.

a The opening-of the holding shunt'24, 25 by the opening of right back contact of CO eliminates the possibility ofanannoyingclick in the telephone switchboard operatorsreceiver in case the tip and ring of plug inserted in I2 or I3 engage up in the transformer primary which current un- V q ro t eley. t re nqf Q- w f re a dulations are ,;impressed 1 and superinduced in the signal circuit by the operation of the aforesaid network. The rise and fall of the E. M. F. of said current undulations causes condensers I4 and I5 to charge and discharge which superinduces corresponding alternating current impulses in the said telephone line circuit and telephonic communication from anyone of the signal boxes 4, 5, 6, I in Ll, L2 and any telephone connected with the said telephone line circuit, by means of jacks I2, I3, is eifectuated. Similarly will the 10 signal circuit and the normally open telephone Iine circuit operativ ely associated as an electric communication system whereby the scope of usefulness of the signal circuit is enlarged, expanded and extended by making it readily available for telephonic communication without, in any way, impairing its normal functioning.

What is claimed is: I '1 relay responsive to alternating current impulse sequences, a signal circuit operatively associated therewith, and a condenser in series between each side of said telephone line circuit and each. side of said signal circuit said condensers impressing in said telephone circuitsaid impulses; operation of said condensers being a function of. variations of E. M. F. in said signal circuit; a telephone net- 5:30 1. A telephone line circuit comprising a line work operatively associated with the aforesaid E. M. F. being superinduced in saidsignal circuit by the operation of said relay and said network.

2. An electric communication system compris densers, each of the two condensers being in series between each of the two sidesof thetwo' circuits, and a telephone network comprising-a telephone transmitter and a transformer, saidnetwork being I operatively associated with said signal circuit and superinducingtherein current undulations corresponding to the variation of 'E. M. F. in said 2 network, the aforesaid condensers superinducing in the aforesaid telephone circuit corresponding alternating current impulses. l

3. An electric communication system comprising a metallic signal circuit, a' telephone'network comprising means of superinducing undulatory corresponding alternating current impulses in said telephone circuit; said telephone circuit com-'* prising battery, a primaryline relay responsive to said alternating current-impulses, a secondary slow to operate line relay responsive to, prolonged operation of;;said primary-line relay,*a; line signal responsiveto operationof said secondary-dine" .rela y, a normally open shunt circuit acrosssaid telephone circuit said shunt circuit being closed by the operation of said secondary line relay; and

signal circuit and comprising a short 'circuiting electromagnetic relay; the aforesaid variations of of said contacts, the closing of one of said contacts inserting signal impulse emitting means in the network and the closing of the other of said contacts short circuiting the secondary winding of said transformer and short circuiting said 5 telephone receiver.

HARRY R. ALLENSWORTH. 

